線粒體是廣泛存在于真核生物中的一種重要的細胞器,，是真核細胞的能量工廠。線粒體含有自身的DNA,，其基因組中包含有核酸序列,、氨基酸序列、基因重排和基因二級結構等各種類型的信息,，為種群遺傳結構,、生物地理學和系統(tǒng)發(fā)育等研究提供了豐富的分子標記。
鱗翅目包括45-48個總科,，是昆蟲綱第二大類群,。雙孔類（Ditrysia）包含了98%的已知鱗翅目物種，被稱為高等鱗翅類,。以前對鱗翅目昆蟲線粒體基因組研究主要集中在雙孔類的7個總科,。這些高等鱗翅目線粒體基因排列相同，與昆蟲線粒體基因的原始排列相比有一個基因發(fā)生重排,。云南蝠蛾（Thitarodes yunnanensis）和人支蝠蛾（Thitarodes renzhiensis）是名貴中藥冬蟲夏草的寄主昆蟲,，屬于外孔類（Exoporia）蝙蝠蛾總科（Hepialoidea），是鱗翅目種低等類群,。
我園協(xié)同進化組曹永強博士在導師楊大榮研究員的指導下,，通過對云南蝠蛾和人支蝠蛾的線粒體全基因組的測序分析，發(fā)現(xiàn)其基因排列與高等鱗翅目不同但與昆蟲線粒體的原始排列一致,，并且在所測蝠蛾屬昆蟲線粒體基因組中沒有發(fā)現(xiàn)高等鱗翅目線粒體基因組共有的一些保守元件,。蝠蛾屬兩種昆蟲線粒體基因組的排列特征揭示了鱗翅目線粒體基因重排發(fā)生在蝙蝠蛾科從其他鱗翅目分離之后。這些特征增加了我們對鱗翅目線粒體基因組結構的認識,，同時對研究線粒體基因組的進化特別是基因重排機制有一定的價值,。
該成果以 The complete mitochondrial genomes of two ghost moths, Thitarodes renzhiensis and Thitarodes yunnanensis: the ancestral gene arrangement in Lepidoptera發(fā)表在BMC Genomics （doi:10.1186/1471-2164-13-276）上。（生物谷Bioon.com）
doi:10.1186/1471-2164-13-276
PMC:
PMID:
The complete mitochondrial genomes of two ghost moths, Thitarodes renzhiensis and Thitarodes yunnanensis: the ancestral gene arrangement in Lepidoptera
Yong-Qiang Cao, Chuan Ma, Ji-Yue Chen and Da-Rong Yang
Background Lepidoptera encompasses more than 160,000 described species that have been classified into 45-48 superfamilies. The previously determined Lepidoptera mitochondrial genomes (mitogenomes) are limited to six superfamilies of the lineage Ditrysia. Compared with the ancestral insect gene order, these mitogenomes all contain a tRNA rearrangement. To gain new insights into Lepidoptera mitogenome evolution, we sequenced the mitogenomes of two ghost moths that belong to the non-ditrysian lineage Hepialoidea and conducted a comparative mitogenomic analysis across Lepidoptera. Results The mitogenomes of Thitarodes renzhiensis and T. yunnanensis are 16,173 bp and 15,816 bp long with an A + T content of 81.28 % and 82.34 %, respectively. Both mitogenomes include 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and the A + T-rich region. Different tandem repeats in the A + T-rich region mainly account for the size difference between the two mitogenomes. All the protein-coding genes start with typical mitochondrial initiation codons, except for cox1 (CGA) and nad1 (TTG) in both mitogenomes. The anticodon of trnS(AGN) in T. renzhiensis and T. yunnanensis is UCU instead of the mostly used GCU in other sequenced Lepidoptera mitogenomes. The 1,584-bp sequence from rrnS to nad2 was also determined for an unspecified ghost moth (Thitarodes sp.), which has no repetitive sequence in the A + T-rich region. All three Thitarodes species possess the ancestral gene order with trnI-trnQ-trnM located between the A + T-rich region and nad2, which is different from the gene order trnM-trnI-trnQ in all previously sequenced Lepidoptera species. The formerly identified conserved elements of Lepidoptera mitogenomes (i.e. the motif 'ATAGA' and poly-T stretch in the A + T-rich region and the long intergenic spacer upstream of nad2) are absent in the Thitarodes mitogenomes. Conclusion The mitogenomes of T. renzhiensis and T. yunnanensis exhibit unusual features compared with the previously determined Lepidoptera mitogenomes. Their ancestral gene order indicates that the tRNA rearrangement event(s) likely occurred after Hepialoidea diverged from other lepidopteran lineages. Characterization of the two ghost moth mitogenomes has enriched our knowledge of Lepidoptera mitogenomes and contributed to our understanding of the mechanisms underlying mitogenome evolution, especially gene rearrangements.
